Control method for commercial washing machine

ABSTRACT

A control method for a commercial washing machine that is capable of reducing washing time unnecessarily wasted during a washing or rinsing operation in which a water supplying process, a washing or rinsing process, a draining process, and a spin-drying process are repeatedly performed according to a corresponding course, the washing or rinsing operation being carried out before a main spin-drying operation, thereby improving the economy of the commercial washing machine is disclosed. The control method includes detecting the amount of laundry after the completion of a draining process, detecting the eccentricity of a drum and determining whether the eccentricity of the drum has been resolved by rotating the drum at an eccentricity detecting RPM after the step of detecting the amount of laundry, and performing a spin drying process with the drum being rotated at different RPMs depending upon the determination as to whether the eccentricity of the drum has been resolved.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2007-0016129, filed on Feb. 15, 2007, which is hereby incorporated by reference in its entirety as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a control method for a commercial washing machine, and more particularly, to a control method for a commercial washing machine that is capable of reducing washing time unnecessarily wasted during a washing or rinsing operation in which a water supplying process, a washing or rinsing process, a draining process, and a spin-drying process are repeatedly performed according to a corresponding course, the washing or rinsing operation being carried out before a main spin-drying operation.

2. Discussion of the Related Art

Generally, a drum type washing machine is a machine that is capable of washing laundry using frictional force generated by the rotation of a washing drum, in which detergent, wash water, and laundry are placed. Consequently, when laundry is washed using the drum type washing machine, damage to the laundry is minimal, and the laundry is not easily tangled. Furthermore, the laundry is washed in a striking and rubbing fashion, and therefore, washing effects are improved.

Generally, the drum type washing machine washes laundry through a washing operation for removing contaminants from the laundry using detergent, a rinsing operation for rinsing the laundry using clean water, and a spin-drying operation for rotating a drum at a high speed to finally remove wash water from the laundry.

In both the washing operation and the rinsing operation, a water supplying process and a draining process are carried out. In addition, a spin-drying process for removing the wash water from the laundry is carried out after the completion of the draining process, such that a washing process and a rinsing process are effectively performed.

During the spin-drying process, the drum is rotated at a higher speed than during the washing process and the rinsing process, and wash water is removed from the laundry by a centrifugal force generated by the rotation of the drum. At this time, if the laundry is eccentrically distributed in the drum, the drum is rotated in an eccentric fashion, with the result that a great load may be applied to a drive unit of the washing machine, and noise may be generated by the drum. For this reason, a process for uniformly rotating the drum at a speed lower than the rotation speed during the spin-drying process to uniformly distribute the laundry in the drum is generally carried out before the commencement of the spin-drying process.

At this time, if the eccentricity of the laundry is not resolved even after the laundry distributing process is carried out, the laundry distributing process is repeatedly carried out. As a result, the laundry distributing process is carried out even at the spin-drying process included in both the washing operation and the rinsing operation, whereby an excessive amount of time is required to perform the washing operation or the rinsing operation.

Especially for a commercial washing machine requiring a user to pay laundry charges, when the washing of the laundry is not completed within a predetermined period of time, extra laundry charges must be paid. Furthermore, if the washing operation is carried out at a Laundromat requiring a short washing cycle, time incurred to complete one washing cycle is excessively increased, with the result that an owner of the Laundromat, seeking to maximize profits through a short washing cycle of the commercial washing machine, may suffer substantial economic losses.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a control method for a commercial washing machine that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a control method for a commercial washing machine that is capable of reducing washing time unnecessarily wasted during a washing operation and a rinsing operation.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a control method for a commercial washing machine, performed during a washing operation, a rinsing operation, and a spin-drying operation, includes detecting the amount of laundry after the completion of a draining process, detecting the eccentricity of a drum and determining whether the eccentricity of the drum has been resolved by rotating the drum at an eccentricity detecting RPM after the step of detecting the amount of laundry, and performing a spin-drying process with the drum being rotated at different RPMs depending upon the determination as to whether the eccentricity of the drum has been resolved.

Preferably, the step of performing a spin-drying process is carried out during the washing operation or the rinsing operation.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings:

FIG. 1 is a sectional view illustrating a general drum type washing machine;

FIG. 2 is a graph illustrating a procedure for entering a spin-drying step after a draining step during a washing or rinsing operation of the drum type washing machine;

FIGS. 3A to 3C are graphs illustrating processes carried out after the completion of a draining step during a washing or rinsing operation of a commercial washing machine according to the present invention;

FIG. 4 is a flow chart illustrating a control method for a commercial washing machine according to the present invention; and

FIG. 5 is a flow chart illustrating a control method of a laundry amount-detecting step according to the present invention in detail.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

FIG. 1 is a sectional view illustrating the structure of a general drum type washing machine. As shown in FIG. 1, the drum type washing machine includes a tub 2 mounted in a machine body 1 such that the tub 2 is supported by a damper 7 and springs 6, a cylindrical drum 3 mounted in the tub 2 such that the drum 3 can be rotated about its horizontal axis, and a drive motor axially coupled to the drum 3.

The drive motor 5 is located at the rear of the tub 2. The drive motor 5 includes a stator 5 a and a rotor 5 b. In order that a driving force from the rotor 5 b is directly transmitted to the drum without a pulley or a belt, a drum shaft 4, which is rotatable along with the drum 3, is directly connected to the rotor 5 b.

At a predetermined position in the front of the machine body 1 is mounted a door 8 corresponding to an opening of the drum 3. Between the door 8 and the drum 3 is mounted a gasket 9 for maintaining sealability in the drum. Above the door 8 is mounted a control panel 10 for allowing a user to input a manipulation command and controlling the overall operation of the washing machine.

In the drum type washing machine with the above-stated construction, a rotating force from the rotor 5 b is transmitted to the drum 3 via the drum shaft 4. During the rotation of the drum 3, laundry in the drum 3 is lifted by lifters 3 a, and then drops due to gravity, whereby a washing operation is carried out.

When the laundry, lifted up by the rotation of the drum 3, reaches a predetermined height, the laundry drops due to gravity, with the result that the laundry collides with wash water in the drum 3. This process is repeatedly carried out, and therefore, the laundry is washed by the friction between the laundry and the wash water.

After the above-described washing process is completed, a spin-drying process is commenced. In the spin-drying process, a drainage pump (not shown) is driven to drain water through a drainage line (not shown), and the drum 3 is rotated at a high speed, whereby the laundry is spin-dried by a centrifugal force.

FIG. 2 is a graph illustrating a procedure for entering a spin-drying step after a wash water draining step during a washing or rinsing operation of the drum type washing machine.

After the draining step is completed during the washing or rinsing operation, the procedure may enter a normal spin-drying step through a laundry amount-detecting step, an eccentricity detecting step, and an intermittent spin-drying step.

The laundry amount-detecting step is a step of detecting the weight of laundry received in the drum. Generally, the laundry amount is detected based on time required until the rotation speed of the drum reaches a predetermined RPM after the rotation of the drum is initiated. With the increase of the laundry amount, time required for the rotation speed of the drum to reach the predetermined RPM increases. Consequently, as shown in FIG. 2, the laundry amount is detected while the rotation speed of the drum is increased or decreased within a range of 50 to 100 rpm, such that the rotation speed of the drum reaches the predetermined rpm.

Here, it is preferred to perform a laundry untangling process entailing rotating the drum to uniformly distribute tangled laundry before the commencement of the laundry amount-detecting step. This is because, when the rotation of the drum is carried out in an eccentric fashion due to tangling of the laundry, noise is generated, and it is difficult to accurately detect the laundry amount. Preferably, therefore, the drum is rotated once or more in alternating directions at a rotation speed of approximately 50 rpm, and then the laundry amount-detecting step is carried out.

After the completion of the laundry amount-detecting step, the eccentricity-detecting step is carried out to detect the eccentricity of the laundry received in the drum and resolve the eccentricity of the laundry. At the eccentricity-detecting step, the drum is rotated at a predetermined rotation speed for a predetermined period of time, such that the laundry is uniformly distributed before entering the spin-drying step.

At this time, the drum is rotated at a speed lower than that during the normal spin-drying process. Preferably, as shown in FIG. 2, the drum is rotated at a rotation speed (rpm₁), which is predetermined between 100 rpm and 120 rpm, preferably at 108 rpm.

Also, the intermittent spin-drying step, which is a preliminary spin-drying step, may be carried out before entering the normal spin-drying step, in order to reduce noise generated when a large amount of water is discharged at once in the first stage of the spin-drying process after the completion of the eccentricity-detecting step and to reduce load applied to the motor. FIG. 2 illustrates that the intermittent spin-drying step is carried out twice. At the first intermittent spin-drying step, the motor is accelerated to 170 rpm (rpm_(1a)), and is then decelerated to 108 rpm (rpm₁). After the motor is decelerated to 108 rpm (rpm₁), a second eccentricity-detecting step is carried out. After the completion of the second eccentricity-detecting step, the second intermittent spin-drying step is carried out. At the second intermittent spin-drying step, the motor is accelerated to 400 rpm (rpm_(1b)), and is then decelerated to 108 rpm (rpm₁).

However, when the eccentricity of the laundry is not resolved at the eccentricity-detecting step, it may be difficult to enter a subsequent intermittent spin-drying step or normal spin-drying step. This is because the drum is rotated at a higher rotation speed at the spin-drying step than at the eccentricity-detecting step, as described above, and therefore, the effect caused by the eccentricity of the laundry is serious at the intermittent spin-drying step or the normal spin-drying step.

For this reason, the eccentricity-detecting step may be repeatedly carried out until the eccentricity of the laundry is resolved. In this case, however, washing time excessively increases. For a commercial washing machine requiring a user to pay laundry charges, however, the increased washing time is economically disadvantageous for the Laundromat.

Hereinafter, therefore, a detailed description will be given of a control method for a commercial washing machine that is capable of preventing the increase of washing time even when the eccentricity of laundry is not resolved at an eccentricity-detecting step.

FIGS. 3A to 3C are graphs illustrating processes carried out after the completion of a draining step during a washing or rinsing operation of a commercial washing machine according to the present invention, and FIG. 4 is a flow chart illustrating a control method for a commercial washing machine according to the present invention.

First, as shown in FIG. 4, when a user inputs a command for process commencement, a water supplying step, a washing or rinsing step, and a draining step are sequentially carried out according to a corresponding washing course (S1 to S3).

After the completion of the draining step (S3), a laundry amount-detecting step is carried out to detect the amount of laundry (S4).

After the completion of the laundry amount-detecting step (S4), an eccentricity-detecting step (S6) is carried out to determine whether the drum is rotated in an eccentric fashion during the rotation of the drum for a predetermined period of time. During the drainage of wash water, the laundry is eccentrically disposed in the drum. Consequently, there is a great possibility that the drum will be rotated in an eccentric fashion. Especially, when the drum is rotated in an eccentric fashion at a spin-drying step at which the drum is rotated at a high speed, the previously mentioned problem may occur. For this reason, the eccentricity-detecting step (S5) is carried out to detect whether the drum is rotated in an eccentric fashion.

At the eccentricity-detecting step (S5), the drum is rotated at a predetermined rotation speed for a predetermined period of time, to move the laundry in the drum. While the laundry is moved in the drum by the rotation of the drum, it is determined whether the eccentric rotation of the drum has been resolved. According to this embodiment, therefore, as shown in FIGS. 3 and 4, the drum is rotated at an eccentricity detecting RPM (rpm₁), such that the laundry is redistributed, and then it is determined whether the eccentricity has been resolved (S5).

The determination as to whether the eccentricity has been resolved is made by detecting the eccentricity amount during the rotation of the drum and determining whether the detected eccentricity amount is more or less than a predetermined reference eccentricity amount. That is, it is determined that the eccentricity has been resolved when the detected eccentricity amount is less than the predetermined reference eccentricity amount. On the other hand, it is determined that the eccentricity has not been resolved yet when the detected eccentricity amount is more than the predetermined reference eccentricity amount.

At this time, it is preferred for the eccentricity detecting RPM (rpm₁) to be less than the rotation speed at the general spin-drying step. In this embodiment, the eccentricity detecting RPM (rpm₁) is set to be approximately predetermined between 100 rpm and 120 rpm, preferably at 108 rpm. However, the eccentricity detecting RPM (rpm₁) is not necessarily limited to the above-defined value.

FIG. 5 is a flow chart illustrating a process for determining whether the eccentricity has been resolved several times at the eccentricity-detecting step.

The eccentricity-detecting step may be carried out once. However, it is preferred for the eccentricity-detecting step to be repeatedly carried out a predetermined number of times, for example n times as shown in FIG. 5.

Specifically, when it is determined that the eccentricity has not been resolved after the drum is rotated at the eccentricity detecting RPM (rpm₁) for a predetermined period of time (t), the eccentricity-detecting step may be repeatedly carried out n times or less. Of course, when it is determined that the eccentricity has been resolved before the eccentricity-detecting step is repeatedly carried out the predetermined number of times (n), the eccentricity-detecting step (S5) is terminated, and then a subsequent spin-drying step is commenced. Also, after the eccentricity-detecting step (S5) is repeatedly carried out the predetermined number of times (n), the eccentricity-detecting step (S5) is terminated, and then the spin-drying step is commenced, even if the eccentricity has not been resolved. In the latter case, however, the predetermined number of times (n) is preferably limited to 5 times or less.

According to the present invention, as described above, the number of times the eccentricity-detecting step is carried out is limited to once or the predetermined number of times (n), even though the eccentricity has not been resolved, whereby it is possible to reduce inefficient washing time. Also, when further reduction of the washing time is required, the intermittent spin-drying step, which will be generally carried out before the normal spin-drying step, may be omitted to reduce the washing time.

According to the present invention, therefore, it is possible to provide a control method for a commercial washing machine that is capable of efficiently using washing time. Also, it is possible to prevent a user from paying extra charges when the washing time is exceeded. Furthermore, it is possible to reduce washing cycle duration, thereby enhancing Laundromat profits.

After the completion of the eccentricity-detecting step (S5), a spin-drying step is commenced. At this time, the spin-drying step may be carried out with the drum being rotated at different rotation speeds, depending upon the determination as to whether the eccentricity has been resolved at the eccentricity-detecting step (S5). As previously described, the faster the rotation speed of the drum is, the greater the effect due to the eccentricity is. Consequently, when the eccentricity has been resolved, the spin-drying step is carried out with the drum being rotated at a normal spin-drying RPM. On the other hand, when the eccentricity has not been resolved, the spin drying step is carried out with the drum being rotated at a rotation speed less than the normal spin-drying RPM.

According to the present invention, as shown in FIG. 4, a formal spin-drying step (S6) or an informal spin-drying step (S7) is selectively carried out depending upon the determination as to whether the eccentricity has been resolved at the eccentricity-detecting step (S5). Specifically, when the eccentricity amount detected at the eccentricity-detecting step (S5) is less than the reference eccentricity amount, the formal spin-drying step (S6) is carried out. On the other hand, when the eccentricity amount detected at the eccentricity-detecting step (S5) is more than the reference eccentricity amount, the informal spin-drying step (S7) is carried out. At the informal spin-drying step (S7), the drum is rotated at an informal spin-drying RPM (rpm₂) for a predetermined period of time (t). At this time, the predetermined period of time (t) is between 10 seconds and 30 seconds, preferably 20 seconds. However, the predetermined period of time (t) is not necessarily limited to the above-defined value.

Specifically, FIG. 3A illustrates a control method characterized in that the eccentricity-detecting step (S5) is carried out once. The spin-drying pattern is selected in an alternative way depending upon one determination as to whether the eccentricity has been resolved. Referring to FIG. 3B, the eccentricity detection is attempted within the limited predetermined number of times (n) until the eccentricity amount detected at the eccentricity-detecting step (S5) is less than the reference eccentricity amount, and, when it is determined that the eccentricity has not been resolved, the informal spin-drying step (S7) is carried out with the drum being rotated at the informal spin-drying RPM (rpm₂) for the predetermined period of time (t).

Here, as shown in FIG. 3A, the informal spin-drying RPM (rpm₂) may be controlled to be the same as the eccentricity detecting RPM (rpm₁) at the eccentricity-detecting step (S5). Alternatively, as shown in FIG. 3B, the informal spin-drying RPM (rpm₂) is preferably more than the eccentricity detecting RPM (rpm₁) and less than a formal spin-drying RPM (rpm₃), which will be described below, at the formal spin-drying step (S6).

When the informal spin-drying RPM (rpm₂) and the eccentricity detecting RPM (rpm₁) are the same, as shown in FIG. 3A, the informal spin-drying step (S7) is carried out with the drum being rotated at the same RPM as the eccentricity detecting RPM (rpm₁) for the predetermined period of time (t), without additional acceleration of the drum after the completion of the eccentricity-detecting step (S5), whereby a reduction in washing time and satisfactory spin-drying effects are achieved.

On the other hand, when the informal spin-drying RPM (rpm₂) is preferably more than the eccentricity detecting RPM (rpm₁) and less than the formal spin-drying RPM (rpm₃) at the formal spin-drying step (S6), as shown in FIG. 3B, the informal spin-drying step (S7) is carried out with the drum being rotated at appropriate RPM for the predetermined period of time (t), without excessive acceleration of the drum in a state in which the eccentricity is not resolved, whereby a reduction in washing time and satisfactory spin-drying effects are achieved.

According to the present invention, meanwhile, when the eccentricity detection is attempted within the limited predetermined number of times (n) until the eccentricity amount detected at the eccentricity-detecting step (S5) is less than the reference eccentricity amount, and, as a result, the eccentricity has been resolved, as shown in FIG. 3C, the formal spin-drying step (S6) is carried out with the drum being rotated at the formal spin-drying RPM (rpm₃) after the completion of the eccentricity-detecting step (S5). At this time, the formal spin-drying RPM (rpm₃) at the formal spin-drying step (S6) is more than the eccentricity detecting RPM (rpm₁) at the eccentricity-detecting step (S5).

At the formal spin-drying step (S6), therefore, the eccentricity detection is attempted within the limited predetermined number of times (n) with the eccentricity-detecting step and the intermittent spin-drying step, which are repeatedly carried out several times, being omitted, and then the spin-drying process is carried out. Consequently, the washing time is reduced. Furthermore, the spin-drying process is carried out at RPM more than that at the informal spin-drying step (S7) in a state in which the eccentricity has been resolved, whereby spin-drying efficiency is further improved.

After the completion of the spin-drying step (S6, S7), the procedure enters a water supplying step, and the remaining washing operation is carried out to complete the washing of the laundry (S8).

As apparent from the above description, the present invention has the effect of providing a short washing cycle satisfying the purpose of a commercial washing machine, thereby improving the economic efficiency of the commercial washing machine.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

1. A control method for a commercial washing machine, performed during a washing or rinsing operation in which the corresponding operation is carried out using wash water and the wash water is discharged, the control method comprising: detecting the amount of laundry received in a drum; detecting the eccentricity of the drum and determining whether the eccentricity of the drum has been resolved, during the rotation of the drum, by rotating the drum for a predetermined period of time such that the laundry can be moved; and performing a spin-drying process with the drum being rotated at different rotation speeds depending upon the determination as to whether the eccentricity of the drum has been resolved.
 2. The control method according to claim 1, wherein the step of performing the spin-drying process is carried out during the washing operation or the rinsing operation.
 3. The control method according to claim 2, wherein the step of detecting the eccentricity of the drum includes rotating the drum at a predetermined rotation speed for the predetermined period of time such that the laundry can be moved, and determining whether the eccentric rotation of the drum has been resolved.
 4. The control method according to claim 3, wherein the determination as to whether the eccentric rotation of the drum has been resolved is made by detecting the eccentricity amount of the drum and determining whether the detected eccentricity amount is less than a predetermined reference eccentricity amount.
 5. The control method according to claim 4, wherein, when it is determined at the step of detecting the eccentricity of the drum that the eccentricity of the drum has not been resolved, the step of performing the spin-drying process is carried out with the drum being rotated at an informal spin-drying RPM for a predetermined period of time.
 6. The control method according to claim 5, wherein the informal spin-drying RPM is more than the RPM at which the drum is rotated at the step of detecting the eccentricity of the laundry.
 7. The control method according to claim 5, wherein the informal spin-drying RPM is the same as the RPM at which the drum is rotated at the step of detecting the eccentricity of the laundry.
 8. The control method according to claim 5, wherein, when it is determined at the step of detecting the eccentricity of the drum that the eccentricity of the drum has been resolved, the step of performing the spin-drying process is carried out with the drum being rotated at a formal spin-drying RPM.
 9. The control method according to claim 8, wherein the formal spin-drying RPM is more than the RPM at which the drum is rotated at the step of detecting the eccentricity of the laundry.
 10. The control method according to claim 8, wherein the formal spin-drying RPM is more than the informal spin-drying RPM.
 11. The control method according to claim 4, wherein the step of detecting the eccentricity of the drum is carried out a predetermined number of times until it is determined that the detected eccentricity amount is less than the reference eccentricity amount.
 12. The control method according to claim 11, wherein the predetermined number of times at the step of detecting the eccentricity of the drum is limited to 5 times or less.
 13. The control method according to claim 11, wherein, when it is determined at the step of detecting the eccentricity of the drum that the detected eccentricity amount is less than the reference eccentricity amount, the step of detecting the eccentricity of the drum is terminated, and the step of performing the spin-drying process is carried out with the drum being rotated at a formal spin-drying RPM.
 14. The control method according to claim 5, wherein the predetermined period of time at the step of performing the spin-drying process is between 10 seconds and 30 seconds.
 15. The control method according to claim 3, wherein the predetermined rotation speed at the step of detecting the eccentricity of the drum is between 100 rpm and 120 rpm.
 16. The control method according to claim 1, further comprising: performing a water-supplying process after the step of performing the spin-drying process.
 17. A control method for a commercial washing machine, performed during a washing or rinsing operation in which a water supplying process, a draining process, and a spin-drying process are repeatedly performed, the washing or rinsing operation being carried out before a final spin-drying operation, the control method comprising: detecting the amount of laundry received in a drum after the draining process is completed; detecting the eccentricity of the drum and determining whether the drum is rotated in an eccentric fashion by rotating the drum for a predetermined period of time such that the laundry is redistributed; and performing a spin-drying process, the step of performing the spin-drying process including performing a formal spin-drying process upon determination at the step of detecting the eccentricity of the drum that the drum is not rotated in the eccentric fashion and an informal spin-drying process upon determination at the step of detecting the eccentricity of the drum that the drum is rotated in the eccentric fashion.
 18. The control method according to claim 17, wherein the rotation RPM of the drum at the step of performing the informal spin-drying process is equal to or greater than the rotation RPM of the drum at the step of detecting the eccentricity of the drum and less than the rotation RPM of the drum at the step of performing the formal spin-drying process. 